TR&D2 Biology to Numerics Project Summary The goals of TR&D Project 2 include development of new capabilities of the Virtual Cell (VCell) (Aims 1-3) and implementation of new technologies for enhancing usability of VCell spatial solvers (Aim 3). The methods of Aims 1 and 2 will enable VCell users to simulate cells that migrate and/or dynamically change their size and shape. The research and development proposed in Aim 3 will markedly improve usability of VCell spatial solvers by making them faster and more robust and by expanding their capabilities. As in the past, new numerical techniques will be rigorously validated before being deployed for general use.